Seeking Help With Dead JDM V5MT1 Mystery

[MrRay]

Hello all,

Forgive the long post that follows.

I have started several posts within Facebook Montero groups but I don’t want anyone to have to go through what I’ve experienced here so I’m returning to the forum world (last time for me was 4x4wire). I’m going to transfer all the info and feedback from the FB posts to this thread so others can benefit moving forward.

The gist:
I need help either sourcing a JDM V5MT1-3
OR
Help modding a USDM V5MT1 to fit
OR
Help repairing my busted JDM V5MT1-3

—-
The long Version:

I am deep into a diesel swap—4d56t/v5mt1 from a JDM 1992 Pajero into my 1991 USDM Montero. Engine out (and sold ?). 4d56t sitting in the engine bay. We discovered the V5 housing is trashed — split in half from the accident that made the Pajero my donor vehicle. Crap.

No problem, we just need to source a V5MT1 from a gen 1 V6 manual truck, right? They’re everywhere. Indeed, we’ve found 2. Unfortunately, and to our pure disgust, the gasser V5’s have a larger input shaft and will not fit through the diesel bellhousing.

Now, I don’t know if the difference is a gas vs diesel thing or a JDM vs USDM thing, or due to the fact that in 1992 the V5MT1 was revised, making it the V5MT1-3. If anyone has some insight I’d be so very thankful.

Potential Solutions:

1) Find a JDM V5MT1-3 from a later Pajero ***no luck so far

2) have the USDM input shaft machined???

3) swap input shaft from the original (busted) JDM into the USDM

4) swap the internals from the JDM into the USDM housing

5) push the f$&ker off a cliff

I am beyond frustrated and on the verge of giving up. This was supposed to be a simple swap but the transmission death changed this into a nightmare. I would be so so grateful for any help or even encouragement here. We are stuck.

Surely I am not the first to ever try this.

Thanks in advance.

Ray

 

[ARDOR]

I'm in the midst of a similar build with my D50, mating a crate D4BF(4D56t) to a V5MT1 out of a '97 MS via a bell housing I sourced from a Triton in Europe, however I haven't gotten to fitting it all together yet so can't comment on whether or not I'll encounter the same issue.


In doing some quick research, primarily older 4x4wire threads, I found the following mentioned regarding the different iterations of the V5MT1-(1-6):

"...95 and after had a different input shaft and different counterbearing..."
1st comment on 12/4/12 - http://4x4wire.com/forums/ubbthreads.php/ubb/printthread/Board/20/main/133404/type/thread.html


If that's true, it might be fruitful to start looking into the different part #s and/or bearing specs for V5MT1 input shafts found on Gen 1s, Gen 2s, and '97-'99 MSs. This thread lists a few:

"front input ME580495
rear output shaft MH044095
rear counter bearing ME580964
front counter bearing ME580496
rear mainshaft bearing ME580799"

V5MT1 gurus. Please have a look inside. Pulled my trans, and it needs help. - 4x4Wire TrailTalk

4x4wire.com

It seems the V5MT1 input shafts are either part # ME580758 or MD725078 depending on the year and model it's out of based off some quick searches here - https://mitsubishi.epc-data.com/


What is the diameter of the input shafts on the replacement V5MT1s you've found vs the JDM unit and the inner diameter of the JDM bell housing?


Best of luck and please post whatever you discover, I know I'll find it valuable info.

 

[JamesW]

Those gearboxes on the 2.5 diesels are quite soft, and it's probably the reason a lot of them were scrapped. A friend of mine blew up 3 of them over 4 years.

Europe is probably your best bet, they were I. The pajero sport, l200 and pajero 2.5 diesel all had them

Sent from my ONEPLUS A6003 using Tapatalk

 

[MrRay]

In doing some quick research, primarily older 4x4wire threads, I found the following mentioned regarding the different iterations of the V5MT1-(1-6):

"...95 and after had a different input shaft and different counterbearing..."
1st comment on 12/4/12 - http://4x4wire.com/forums/ubbthreads.php/ubb/printthread/Board/20/main/133404/type/thread.html


If that's true, it might be fruitful to start looking into the different part #s and/or bearing specs for V5MT1 input shafts found on Gen 1s, Gen 2s, and '97-'99 MSs...

...What is the diameter of the input shafts on the replacement V5MT1s you've found vs the JDM unit and the ID of the JDM bell housing?

Wow, great info! You’re better than I at this part # and forum search detective work. I did several searches in the 4x4wire Tech and Diesel archives but didn’t have much luck. I’ve mostly found vague references like on a D50 forum: “yeah, you’ll need to machine the input shaft.” Then no elaboration or replies.

This tech article has some very specific info, though I haven’t been able to confirm it.

http://tcase.rsgear.com/articles/1997_06.pdf

According to this article, the V5MT1 was updated (better synchro design, as you stated) in 1992. It was then designated V5MT1-3. What year is your bellhousing from? Perhaps it’s not a gas vs diesel thing. Maybe instead it’s this update. Maybe they used a smaller input shaft when the updated it???

According to it, the -2 was used on Gen 1 trucks through 91. Then the -3 with updated synchros came in 92. So that conflicts with what you read about it switching in 95. I can say with certainty that the 92 JDM V5MT1 (whatever iteration I have—chassis plate just says “V5MT1”) has a smaller input shaft that all the Gen1 V5’s we’ve found.

Here are the input shaft measurements we have:
The 92 JDM diesel: 25.5mm
89 Raider V6 M/T: 29mm

 

[MrRay]

A friend of mine blew up 3 of them over 4 years.

Europe is probably your best bet, they were I. The pajero sport, l200 and pajero 2.5 diesel all had them

Well I certainly don’t want to go through this process every year!

Yeah, import is the conclusion I’m coming to. I’ve found that so few people are aware of the incompatibility between years that you can’t trust the people selling them here in the US (not for dishonesty, they just don’t know). I’m working on making some contacts in that regard. Will update if I have any luck.

 

[ARDOR]

Those gearboxes on the 2.5 diesels are quite soft, and it's probably the reason a lot of them were scrapped. A friend of mine blew up 3 of them over 4 years.

Do you happen to know what went wrong with or what year and model vehicles the 3x units he went through came from?

I know many 2.5 4D56t/D4BFs are swapped into 2.6 D50/MM/Gen Is w/weaker FM145 transmissions as the 2.6/FM145/4D56t/D4BF share the same bellhousing pattern.

The article MrRay has linked to seems to contradict this claim and is more reflective of what I've always read about the V5MT1, that it's a simple and rather stout iron bodied transmission derived from Mitsubishi's commercial truck line:

"Mitsubishi has a passion for alpha-numeric codes for transmission identification, but if you understand the codes it makes perfect sense. The first letter V identifies the type of drivetrain. V is the code for 4WD based on rear-wheel-drive. The second digit is the number of forward speeds, in this case 5. The third digit is either A for an automatic or M for a manual transmission. The fourth digit stands for the manufacturer of the unit. If the fourth digit is a number, it means that the unit was designed by the passenger-car engineering division of Mitsubishi Motor Corp. The letter T in this unit means it was produced by the truck and bus division of Mitsubishi. The 5th digit is the development order. The second design is denoted by a 6th digit as in the 1992 version V5MT1-3.

The V5MT1 is a much heavier, stronger unit that the FM145 it replaced. It's a cast-iron-case, top loaded transmission, with detachable bellhousing and provision for power takeoff."

http://tcase.rsgear.com/articles/1997_06.pdf

The bell housing I have is from a UK market 2006 L200, K74 model, and has a +/- 25mm hole as well; it's difficult to get my calipers within the housing to get a truly accurate measurement.

The V5MT1 I have is out of a '97 MS, K96W model / Vin # JA4MT31P2VP004615, but is still installed in the parts truck I bought so I can't yet verify the diameter of it's output shaft. Perhaps I'll find some time to pull it this week, as I need to do so anyway.


In doing more digging it appears that there are two different and distinct output shafts available for the V5MT1, as well as litanies of different part #s for each, based upon the vehicle's configuration and market.

One has a narrower shaft, which I would presume fits the +/- 25mm bell housings we have, is commonly seen under part # ME580758 and seemingly found in Japanese and European market vehicles:

http://www.euro4x4parts.com/parts/vev1055_input_shaft_ME580758.html

The other has a thicker shaft, which I would guess is the same as the +/- 29mm shafts found in US domestic market V5MT1s from D50/MM/Gen 1 & II/MSs and can be found pictured in this very through input shaft replacement tutorial from a Russian language site:

МКПП(V5MT1), достаём первичный вал.

Всех приветствую! На недавно купленной мною б/у мкпп есть косячёк с первичным валом, а именно износ шейки опорного подшипника. Чтобы извлечь первичный вал, надо разобрать практически всю коробку. Опиш…

translate.google.com

Original Russian version - https://www.drive2.ru/l/7833015/


Apart from the difference in the shaft diameter between the bearing race and splines, they appear to be the same. However without having them both in hand, it's impossible to confirm that suspicion and verify if they would swap back and forth or not.

MrRay, since you happen to be in that very situation, were you to remove the output shafts from both your JDM and US market V5MT1s and verify that the shaft diameters are all that differ, it would be a fairly easy operation to rebuild your US V5MT1 w/the narrower JDM input shaft.

If there are in fact differences other than the shaft diameter, with both in front of you, it'd be possible to determine whether or not the thicker US shaft could be chucked in a lathe and narrowed enough to work with the JDM bell housing; I struggle to foresee any reason this wouldn't work unless there's some difference in length or spline count/specs, which would really shock me.


This seems to me to be the simplest/cheapest/most straight forward option/solution requiring no additional parts beyond a few seals and bearings; the Russian tutorial linked above is very through w/lots of clear pics and appears to be a fairly straight forward procedure.

Such information would be immensely valuable to myself and any others who may undertake this swap in the future, enabling us to avoid this dilema by either ordering the JDM ME580758 unit or narrowing the thicker US shaft in a lathe...


Otherwise sourcing a bell housing with a +/- 29mm opening would be my second suggestion, as it would be pretty light and easy to ship and there doesn't look to be enough material on the existing bell housing sleeve to remove +/- 1.75mm of material from it w/o compromising its integrity for the through out bearing.

 

[MrRay]

Do you happen to know what went wrong with or what year and model vehicles the 3x units he went through came from?

I know many 2.5 4D56t/D4BFs are swapped into 2.6 D50/MM/Gen Is w/weaker FM145 transmissions as the 2.6/FM145/4D56t/D4BF share the same bellhousing pattern.

The article MrRay has linked to seems to contradict this claim and is more reflective of what I've always read about the V5MT1, that it's a simple and rather stout iron bodied transmission derived from Mitsubishi's commercial truck line:

"Mitsubishi has a passion for alpha-numeric codes for transmission identification, but is you understand the codes it makes perfect sense. The first letter V identifies the type of drivetrain. V is the code for 4WD based on rear-wheel-drive. the second digit is the number of forward speeds, in this case 5. The third digit is either A for an automatic or M for a manual transmission. The fourth digit stands for the manufacturer of the unit. If the fourth digit is a number, it means that the unit was designed by the passenger-car engineering division of Mitsubishi Motor Corp. The letter T in this unit means it was produced by the truck and bus division of Mitsubishi. The 5th digit is the development order. the seconds design in denoted by a 6th digit as in the 1992 version V5MT1-3.

The V5MT1 is a much heavier, stronger unit that the FM145 it replaced. It's a cast-iron-case, top loaded transmission, with detachable bellhousing and provision for power takeoff."

http://tcase.rsgear.com/articles/1997_06.pdf

The bell housing I have is from a UK market 2006 L200, K74 model, and has a +/- 25mm hole as well; it's difficult to get my calipers within the housing to get a truly accurate measurement.

The V5MT1 I have is out of a '97 MS, K96W model / Vin # JA4MT31P2VP004615, but is still installed in the parts truck I bought so I can't yet verify the diameter of it's output shaft. Perhaps I'll find some time to pull it this week, as I need to do so anyway.


In doing more digging it appears that there are two different and distinct output shafts available for the V5MT1, as well as litanies of different part #s for each, based upon the vehicle's configuration and market.

One has a narrower shaft, which I would presume fits the +/- 25mm bell housings we have, is commonly seen under part # ME580758 and seemingly found in Japanese and European market vehicles:

View attachment 537243

http://www.euro4x4parts.com/parts/vev1055_input_shaft_ME580758.html

The other has a thicker shaft, which I would guess is the same as the +/- 29mm shafts found in US domestic market V5MT1s from D50/MM/Gen 1 & II/MSs and can be found pictured in this very through input shaft replacement tutorial from a Russian language site:

View attachment 537244

МКПП(V5MT1), достаём первичный вал.

Всех приветствую! На недавно купленной мною б/у мкпп есть косячёк с первичным валом, а именно износ шейки опорного подшипника. Чтобы извлечь первичный вал, надо разобрать практически всю коробку. Опиш…

translate.google.com

Original Russian version - https://www.drive2.ru/l/7833015/


Apart from the difference in the shaft diameter between the bearing race and splines, they appear to be the same. However without having them both in hand, it's impossible to confirm that suspicion and verify if they would swap back and forth or not.

MrRay, since you happen to be in that very situation, were you to remove the output shafts from both your JDM and US market V5MT1s and verify that the shaft diameters are all that differ, it would be a fairly easy operation to rebuild your US V5MT1 w/the narrower JDM input shaft.

If there are in fact differences other than the shaft diameter, with both in front of you, it'd be possible to determine whether or not the thicker US shaft could be chucked in a lathe and narrowed enough to work with the JDM bell housing; I struggle to foresee any reason this wouldn't work unless there's some difference in length or spline count/specs, which would really shock me.


This seems to me to be the simplest/cheapest/most straight forward option/solution requiring no additional parts beyond a few seals and bearings; the Russian tutorial linked above is very through w/lots of clear pics and appears to be a fairly straight forward procedure.

Such information would be immensely valuable to myself and any others who may undertake this swap in the future, enabling us to avoid this dilema by either ordering the JDM ME580758 unit or narrowing the thicker US shaft in a lathe...


Otherwise sourcing a bell housing with a +/- 29mm opening would be my second suggestion, as it would be pretty light and easy to ship and there doesn't look to be enough material on the existing bell housing sleeve to remove +/- 1.75mm of material from it w/o compromising its integrity for the through out bearing.

 

[MrRay]

Hey what a great post! Thanks for all the detail you took attention to. I will absolutely do what I can to help those who follow not have to go through the same frustrations! I think we should look at swapping input shafts first. Will report back once we get into that.

 

[JamesW]

It was a 93 I think, box would get noisy, then eventually every gear in it would be a neutral the rear axle also snapped on that one, which was fixed in later models, they would break on the weld where the shafts meet the diff

Sent from my ONEPLUS A6003 using Tapatalk

 

[ARDOR]

I will absolutely do what I can to help those who follow not have to go through the same frustrations! I think we should look at swapping input shafts first. Will report back once we get into that.

That's what I would do.

Fortunately you're in a position where you have both JDM and US input shafts on hand to definitively determine their interchangeability and potentially alleviate your issue immediately by swapping the JDM shaft into the US V5MT1 without having to source, or wait on, parts from far corners of the globe.

Additionally, you'll have the piece of mind of knowing the actual internal condition of the transmission gears/syncros/bearings/etc, confirm your unit has the upgraded syncros, and the opportunity to replace any other damage found; cheap insurance when you're already so invested in this project.

I'm looking forward to hearing back on what you discover, anxious to know if the shafts are the same save for the shaft diameter of if there are other differences between them, tooth counts, bearing race width/diameters, tapers, lengths, spline count/depths, etc.

It was a 93 I think, box would get noisy, then eventually every gear in it would be a neutral

the rear axle also snapped on that one, which was fixed in later models, they would break on the weld where the shafts meet the diff

That's odd, I wonder if they were earlier iterations of the V5MT1 w/paper lined syncros or if perhaps someone had run them w/GL-5 fluid at any point. There was a service bulletin about the necesity of GL-4 fluid:

friction modifier for V5MT1

Looking at a '90 TSB on lubrication. It says to add this mitsu modifier that comes with the syncho kit to 75/85 w gl-4. Is this modifier the same as LSD additve by StaLube?

4x4wire.com

Its also a bit surprising to hear he snapped a rear axle, the 9" rear ends seem to be regarded as being overbuilt and nearly bullet proof...

 

[MrRay]

Update:
We are digging into the two trannies we have—the -2 from an 89 Raider and the original -3 from the JDM Pajero. Going to check feasibility of either swapping entire internals or at least just the input shaft. It appears the latter is potentially a straight forward swap. Hope to have pics and measurements soon!

 

[ARDOR]

That's great to hear.

Would you mind taking note of the Mitsubishi part # on the side of the JDM V5MT1 so that if it's determined it's input shaft will fit the US market V5MT1 we might be able to determine the appropriate input shaft part #?

Thanks!

 

[lordtrunks]

na3s i used your vin number for your donor sport and the asa program shows yours has ME581629 as the main shaft part number, ME580147 snap ring, ME580495 bearing, there are 2 part numbers for the needle bearings MH044095 is the replacement and ME602443 which is was the original so they must have changed something with that and ME580789 rear snap ring on that shaft

 

[lordtrunks]

actually the 9" rear axle shafts are the same 28 spline shafts the 8" diff uses we'd twist those up back in the day before my self and others swapped to the 9.5 diff with 31 spline axles

 

[lordtrunks]

if you have the chassis number for that jdm i can look up the part numbers for that aswell